postgresql11 主从配置详解

以下内容是针对pgsql11来做的。请看好版本再去考虑是否往下看

准备两台服务器，地址如下： 

主：192.168.0.1	pgsql11
从:192.168.0.2	pgsql11

 一、主库配置

1、创建具有复制权限的用户replica 密码为000000

CREATE ROLE replica login replication encrypted password 'xxxxxx';

2、修改postgresql.conf

首先创建归档目录：mkdir -p /var/lib/pgsql/11/data/archive。我这边是放到了我数据存储的相关目录。注意：归档目录必须要对postgres用户授权。否则启动会报错。

把postgresql.conf有关信息改成以下内容

listen_addresses = '*'            # what IP address(es) to listen on;
port = 5432                # (change requires restart)
max_connections = 1000            # (change requires restart)
shared_buffers = 128MB            # min 128kB
dynamic_shared_memory_type = posix    # the default is the first option
wal_level = replica        # minimal, replica, or logical
archive_mode = on        # enables archiving; off, on, or always
archive_command = 'cp %p  /var/lib/pgsql/11/data/archive/%f'     

# command to use to archive a logfile segment
wal_sender_timeout = 60s    # in milliseconds; 0 disables
hot_standby = on            # "on" allows queries during recovery
max_standby_streaming_delay = 30s    # max delay before canceling queries
wal_receiver_status_interval = 10s    # send replies at least this often
hot_standby_feedback = on        # send info from standby to prevent
log_directory = 'log'    # directory where log files are written
 

3、修改pg_hba.conf

把以下内容放到host最后一行。切记一定要放到最后，不然不进行复制工作。如图所示：

host replication replica 192.168.0.2/32 trust 

 4、重启主库

systemctl reload pgsql.service

这边顺带絮叨下，systemctl配置pgsql启动。

利用root权限进到目录 cd /etc/systemd/system

然后通过vi pgsql.service创建个新文件。把以下内容放到pgsql.service中。注意改下相关路径

[Unit]
Description=PostgreSQL database server
After=network.target
[Service]
Type=forking
User=postgres
Group=postgres
Environment=PGPORT=5432
Environment=PGDATA=/var/lib/pgsql/11/data/
OOMScoreAdjust=-1000
ExecStart=/usr/pgsql-11/bin/pg_ctl start -D ${PGDATA} -s -o "-p ${PGPORT}" -w -t 300
ExecStop=/usr/pgsql-11/bin/pg_ctl stop -D ${PGDATA} -s -m fast
ExecReload=/usr/pgsql-11/bin/pg_ctl reload -D ${PGDATA} -s
TimeoutSec=300
[Install]
WantedBy=multi-user.target
 

然后执行以下命令启用服务控制守护

systemctl daemon-reload 

配置开机启动 

systemctl enable pgsq.service

二、配置从库

1、验证下主库是否配置成功

[root@localhost data]# psql -h 192.168.0.1 -U postgres

psql (11.18)

Type "help" for help.

postgres=#

2、停止从库

systemctl stop pgsql.service

3、清空data数据存储

把data下的数据全清除。因为第四步要拉取主库的信息

rm -rf /var/lib/pgsql/11/data/*

4、从主库拉取数据

192.168.0.1：主库ip

pg_basebackup -h 192.168.0.1 -U replica -D /var/lib/pgsql/11/data/ -X stream -P

5、从库配置postgresql.conf

第四步拉取后的postgresql.conf文件，其实和主库中的postgresql.conf是一致的。检查下没问题就可以了

把postgresql.conf相关内容改成如下。注意归档文件的创建。

mkdir -p /var/lib/pgsql/11/data/archive/

listen_addresses = '*'            # what IP address(es) to listen on;
port = 5432                # (change requires restart)
max_connections = 1000            # (change requires restart)
shared_buffers = 128MB            # min 128kB
dynamic_shared_memory_type = posix    # the default is the first option
wal_level = replica        # minimal, replica, or logical
archive_mode = on        # enables archiving; off, on, or always
archive_command = 'cp %p /var/lib/pgsql/11/data/archive/%f'        # command to use to archive a logfile segment
wal_sender_timeout = 60s    # in milliseconds; 0 disables
hot_standby = on            # "on" allows queries during recovery
max_standby_streaming_delay = 30s    # max delay before canceling queries
wal_receiver_status_interval = 10s    # send replies at least this often
hot_standby_feedback = on        # send info from standby to prevent
log_directory = 'log'    # directory where log files are written

5、在data目录下修改或创建recovery.conf文件。如果不存在就自己创建

# 调整参数：
recovery_target_timeline = 'latest'   #同步到最新数据
standby_mode = on          #指明从库身份
trigger_file = 'failover.now'
primary_conninfo = 'host=192.168.0.1 port=5432 user=replica password=xxxxxx'   #连接到主库信息

6、启动从库

systemctl start pgsql.service

然后再主库中执行

select client_addr,sync_state from pg_stat_replication;如果有从库节点信息。表示已经创建成功了。可以实验从主库插入一条数据，不出意外的话。从库会同步到此条数据。